Ultra-high performance fibre reinforced concrete (UHPFRC) is an innovative cement-based engineering material. The mechanical properties of UHPFRC not only depend on the properties of the concrete matrix and fibres, but also depend on the interaction between these two components. The fibre distribution is affected by many factors and previous researchers had developed different approaches to test the fibre distribution. This research adopted the non-destructive C-shape ferromagnetic probe inductive test and investigated the straight steel fibre distribution of the UHPFRC plate. A simplified characterization equation is introduced with an attenuation factor to consider the different plate thicknesses. The effective testing depth of this probe was tested to be 24 mm. By applying this method, fibre volume content and the fibre orientation angle can be calibrated for the entire plate. The fibre volume content generally fulfilled the design requirement. The fibre orientation angle followed a normal distribution, with a mean value of 45.60°. By testing small flexural specimens cut from the plates, it was found out that the mechanical performance (peak flexural strength) correlates with the product of fibre volume content and cosine fibre orientation angle.

Traditional disposal methods such as landfilling and land reclamation are insufficient to mitigate the environmental impact of construction spoil, making non-sintered blocks a promising approach for resource utilization. This study investigates the production and performance of steel slag soil blocks as an alternative to conventional cement-based materials for non-sintered blocks. The optimal manufacturing parameters were identified as a sodium silicate solution with 6% Na₂O, 30% steel slag content, a liquid/solid ratio of 0.18, and a forming pressure of 10 MPa, achieving a peak compressive strength of 14.46 MPa. Further, the synergistic combination of alkali activation and carbonation enhanced compressive strength to 17.4 MPa, attributed to the development of a compact microstructure characterized by a honeycomb-like C-(A)-S-H gel and well-crystallized, triangular-shaped aragonite. However, durability tests under freeze-thaw and wet-dry cycles revealed that carbonation can detrimentally affect performance. The transformation of C-(A)-S-H gel into calcium carbonate, with relatively weaker cementitious properties, led to internal cracking and surface detachment. Micro-CT analysis confirmed ring-like patterns under freeze-thaw conditions and diagonal cracks during wet-dry cycling, whereas reference blocks incorporating 30% ordinary Portland cement maintained superior compactness with no cracks. These findings suggest that although the alkali activation and carbonation process enhances early strength, further optimization is necessary to improve long-term durability before broader application can be recommended.